1. Field of the Invention
The present invention relates generally to a recording system and in particular concerns a system for controlling relative movement between recording means and ruled lines printed on a recording sheet.
2. Description of the Prior Art
Usually, a recording system or apparatus for recording data on a recording strip or sheet is employed as one of the means for displaying the analysis results of analyzing apparatus, output informations from various measuring instruments. The analyzed results are recorded on the recording sheet strip with a certain physical quantity taken along the abscissa as a first variable, while a second physical quantity related to the first quantity is taken along the ordinate. For the quantity taken along the abscissa, there may be enumerated, for example, wavelength or wavenumber in a spectrophotometer, retention time in the case of a chromatograph such as gas or liquid chromatograph, massnumber in the case of a mass spectrum measured by a mass spectrometer, chemical shift in a absorption spectrum in the case of a nuclear magnetic resonance spectrometer and so forth. In most cases of the measurement systems, time is taken along the abscissa.
For the recording of the analyzed results on a recording sheet, it is a prerequisite that the analyzed results are recorded in one-to-one correspondence to the abscissa and the ordinate, respectively. On this assumption, a sample is analyzed in respect of quality or quantity. Accordingly, in order to carry out an analysis with a high accuracy, it is required that variation or displacement in the abscissa direction can be readily read with a high accuracy. In order to meet such requirement, the recording sheet or strip is usually printed with ruled lines with a predetermined inter-line space in the ordinate direction thereof. Various rules or line spaces are adopted. However, the most familiar is a recording sheet printed with an inter-line space of 1 cm. As an attempt to incerease the accuracy, there may be employed a marker system which is adapted for recording a short marker for a space of 1 mm, an intermediate marker for a space of 5 mm and a long marker for a space of 10 mm, for example.
However, if a facilitated reading of variation along the abscissa is of a primary concern, it is preferred to make use of the ruled lines printed previously on the recording sheet. In this case, when spectrum in the wavelength range of 300 nm to 400 nm is to be recorded in the measurement with a spectrophotometer, operator sets at first the position of a recording or writing pen in alignment with a given one of the ruled line in precedence to the starting of the measurement. Assuming that the recording sheet is fed in the abscissa direction at a feeding rate of 20 nm/cm, displacements such as 320 nm, 340 nm and so forth can be offhand read with the space of 20 nm. The positional coincidence between the recording pen and one of the ruled lines in precedence to the initiation of the measurement is required also in the case where the marker system is utilized, because otherwise the ruled line will not be aligned with the marker, thereby reducing the advantages provided by the use of the ruled lines. On the contrary, the presence of the ruled lines may provide obstacle for the reading along the abscissa.
In conjunction with the use of the ruled lines on a recording sheet, there has heretofore been a problem that the writing pen position has to be brought into alignment with a selected one of the ruled lines every time when the measurement is initiated, involving cumbersome manipulation. In conventional measurements, the recording pen will not always coincide with the ruled line after completion of a single measurement. Rather, misalignment will occur more frequently. Accordingly, for the recording with the aid of the ruled lines, operation for aligning the pen position with a selected one of the ruled lines is required for every measurement, which is of course a troublesome procedure.